Hydraulic fracturing, or fracking, is a process used to recover natural gas, oil, or other fossil fuels from rock layers deep below ground level. A typical hydraulic fracturing process includes multiple trucks pumping a pressurized liquid mixture of water, sand, and chemicals into a wellhead above the surface, which feeds into a wellbore extending below the surface to the desired depth. The wellbore includes casings that have perforated sections that allow the liquid to escape into the rock layer.
As the pressurized liquid is pumped through the wellbore below the surface, the pressurized liquid will be forced through the perforated sections and into the surrounding formation to cause the rock to fracture. The liquid will continue to flow into these fractures, creating fissures. During the process, the pressure of the liquid is monitored and the ratio of sand to water can be increased as the fracturing job progresses. The process maintains the highest pressure possible to ensure maximum fracturing in the rock.
When the fracturing process is complete, the pressure is reduced, and the liquid is released from the wellbore. The sand from the mixture remains within the fissures created by the fracturing, allowing the natural gas or oil to flow and be recovered.
Because of the nature of the process, fluid pumps and delivery lines that feed the fracking fluid into the wellbore operate under high pressure, such as approximately 6,000 to 15,500 psig. The pressure within the system is monitored to ensure that the system operates as desired. However, pressure spikes can occur throughout the system that if sufficiently high could cause piping to break or weaken, ultimately leading to subsequent breaking due to fatigue.